JP2835201B2 - Baseball bat - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a baseball bat.

[0002]

BACKGROUND OF THE INVENTION Over the years, numerous hollow metal baseball bat designs have been disclosed. For example, U.S. Patent No. 4,2,2, issued February 3, 1981 to Easton.
See No. 48,425. Some of these designs include inserts that are intended to dampen vibration when hitting the ball and to improve the impact resistance of the bat. An example of this type of design is described in H. H. on June 15, 1976. US Patent No. 3,8 issued to Fujii
No. 61,682 and April 6, 1982, J.I. Ish
No. 4,323,239 issued to ii.

[0003] Various composite tubular elements, in which the metal tube is provided with an outer wrapping of carbon-reinforced fibers, are described in November 6, 1979.
U.S. Patent No. 4,173,670, issued on Jan. 19, 1992;
U.S. Pat. No. 4,131,701 issued Dec. 26, 78; U.S. Pat. No. 4,084,819 issued Apr. 18, 1978; U.S. Pat. No. 4,082,277 issued, 1
U.S. Pat. No. 4,02, issued May 17, 977
3,801 (all of these are Richard L.V.
issued to An Auken).

Some attempts have been made to coat or package the outer surface of a metal bat with a material intended to improve hitting performance. An example of this kind of design is
On March 24, Y. It is disclosed in U.S. Pat. No. 4,025,377 issued to Tanikawa.

[0005]

Generally speaking, the outer packaging and coating of tubular metal articles is an important improvement for articles which are subject to external shocks or other forces, such as baseball bats and bicycle parts. Does not bring. This is especially true for bicycle seat tubes which are clamped inside the frame. This is because if the frame tube were clamped directly to the carbon fiber, the carbon fiber on the outer surface of the seat tube would be damaged and would lose its structural integrity.

[0006]

DISCLOSURE OF THE INVENTION An internal reinforcing metal tube structure having at least one carbon fiber layer on the internal surface is disclosed herein. A preferred embodiment is a metal baseball bat, which has an elongated hollow metal tubular body, a portion of which is designated as the ball hitting area. In the ball hitting area, the wall thickness of the hollow metal body may be thin. This is achieved by forming a depression in the inner wall surface of the body.

[0007]

A reinforcing member in the form of a hollow sleeve is fitted into the hollow of the main body. Decide to happen. This compression fit locks the sleeve in the recess and provides a high wall recovery rate upon impact in the ball striking area of the bat.

[0008]

BRIEF DESCRIPTION OF THE DRAWINGS Other objects, features and advantages will become apparent from the following description taken in conjunction with the drawings. In the drawings, the same reference numerals indicate the same components.
In the following, the invention will be described with particular reference to a metal baseball bat.

Referring to FIG. 1, there is shown in cross section a hollow metal tube 12 used to manufacture a bat 10 in accordance with the teachings of the present invention. Tube 12 includes a generally cylindrical body 14, a taper 16, and a grip 18 terminating in a knob 20.

The body 14 preferably includes a recess 24 formed in the inner wall of the tube 12, as shown in FIG. The indentation 24 is due to the result of reducing the wall thickness of the tube 12 in the region of the torso 14 where the ball is hit by the bat 10.

For example, the tube 12 is of type CU3
Aluminum alloy tubing using alloys such as 1,7046,7178. The desired shape of the tube 12 can be obtained by continuously drawing aluminum alloy tubing with the desired outer diameter until the desired inner wall contour is obtained. The method of drawing a tube to create a body cavity is known as batting.

The wall thickness of the tube 12 in the region of the recess 24 is typically 40 times the unwalled wall thickness of the tube 12 in the region of either end of the recess 24.
% To 60%. Thus, for example, the wall thickness at the recess is typically from 0.05 inches (1.27 mm) for a bat having a wall thickness of 0.08 inches (2.03 mm) without the recess. The wall thickness without depressions can range up to 0.08 inches (2.03 mm) for a bat with 0.12 inches (3.05 mm).

The composite sleeve 26 is formed by wrapping a sheet of carbon fiber and matrix on an expandable mandrel. In a preferred embodiment of a baseball bat,
The fibers are carbon fibers oriented in a bidirectional 90 ° woven fabric configuration. Other orientations of carbon fibers may also be desirable for other types of articles, depending on the end use in which the article is to be laid. The fibers are supported within a matrix containing, for example, a thermosetting resin, such as an epoxy, which remains soft and pliable until thermoset. The combination of fiber and base material constitutes a flexible sheet. As will be apparent to those skilled in the art, a thermoplastic resin can be used in place of the thermosetting resin.

The sleeve 26 is formed as follows.
The above-described sheet material is placed in the final sleeve 26 by indentation 2.
4. The width is determined so that it can be fitted into the inside of the base. The sized sheet is then wrapped around an inflatable mandrel containing an expandable bag as is well known in the art. Alternatively, an expandable solid mandrel of an elastic material such as silicone with a pull bolt extending longitudinally may be used. The number of times the sheet is wrapped around the mandrel can vary from once to multiple times, depending on the desired characteristics of the finished bat 10. Usually 3
It is winding of times.

The diameter of the mandrel when not expanded is
It is determined that the wrap sheet forming the sleeve 26 can be inserted into the tube 12 through the end 22. Expanding the mandrel with bag air pressure of about 80 pounds per square inch (square kilogram per square inch) when sleeve 26 is adjacent to recess 24, or using a solid mandrel Then, a pull bolt is pulled to compress the solid mandrel in the axial direction and expand it in the radial direction. The expanded mandrel also expands the sleeve 26 and presses it against the inner wall of the recess 24. In order to secure the sleeve 26 to the body 14, a film adhesive such as type FM73 manufactured by American Cyanamid or a glass fiber insulator may be applied to the inner wall of the recess 24 prior to insertion of the sleeve 26. Of carbon fiber,
The preferred orientation with respect to the axis of the bat is 0 ° for one half of the woven fiber and 90 ° for the other half.

The entire assembly of tube 12 and expanded sleeve 26 is then brought down to about 250 ° F by about 4 ° C.
Heat set by raising in 5 minutes. During the cure cycle, maintain air pressure in the bag or maintain appropriate tension on the pull bolt.

During the heat curing, the aluminum tube 12 expands slightly due to a rise in temperature.
6 is possible. After the cure cycle, the tubes also shrink as the assembly cools, but now the cured sleeve does not substantially shrink. This is because the coefficient of thermal expansion of the aluminum tube is much greater than the coefficient of thermal expansion of the carbon fibers of the sleeve. Thus, the cooling tube shrinks over the cured sleeve 26,
It produces significant compressive forces on the order of thousands of pounds per square inch. The carbon composite sleeve handles these forces without buckling, thus creating a preload stress on the sleeve. Once the assembly has cooled, the expandable mandrel can be removed from tube 12 by depressurizing the bag or by loosening the pull bolt.

According to the above-described structure of the bat 10, the aluminum wall of the ball hitting portion of the bat can be made very thin, and as a result, the weight and the inertia can be reduced as compared with the conventional metal bat. . One example of a bat constructed in accordance with the teachings of the present invention has an "empty weight" of minus 13 oz. Negative or negative empty weight is obtained when the weight of the bat (oz) is subtracted from the length of the bat (inch). For example, 34 inches (86.3)
A typical conventional bat, 6 cm in length, typically has a length of about 34
Ounces (963.9 g) and therefore have no significant negative empty weight. A negative empty weight allows the bat to swing faster with the same energy input than a heavier bat. As a result, a considerable impact is applied to the ball when it comes into contact with the ball.

The above-described contraction of the body 14 causes the locking operation of the sleeve 26 in the recess 24. Further, by providing the composite sleeve 26 in the aluminum body 14, the composite sleeve can be protected from the crushing force generated by the direct impact from the ball. The bat 10 made in this way has no damage to the composite sleeve and has high durability. And sequentially, the sleeve
Gives the bat a higher wall recovery when hitting. This is due to the low inertia and high bending stiffness of the wall resulting from the higher modulus of the carbon fiber matrix.

Although the use of the present invention has been specifically described in connection with a bat having a recess, those skilled in the art will readily appreciate that the recess is not a requirement for practicing the present invention.

[Brief description of the drawings]

FIG. 1 is a cross-sectional view of a hollow metal tubular body of a metal bat constructed in accordance with the teachings of the present invention.

FIG. 2 is a cross-sectional view of a metal bat body similar to the body of FIG. 1 having a rolled end and having an internal recess with a reinforcing sleeve installed therein.

FIG. 3 is a sectional view taken along line 3-3 in FIG. 1, showing a state in which a reinforcing sleeve is installed on the inner surface of the main body of the metal bat.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 10 Butt 12 Hollow metal tube 14 Cylindrical body 16 Tapered part 18 Handle part 20 Knob 24 Recess 26 Composite sleeve

──────────────────────────────────────────────────続 き Continued on the front page (72) Inventor Roger Sudders United States 92064 Powey Pomerad Road, California 12748 (72) Inventor Charles Teixeira, United States of America 93543 Little Rock, East Avenue, Ave 8 11647 (56) References Sho-62-21380 (JP, U) Shokai Hei 3-24168 (JP, U) Sho-kai 62-39758 (JP, U) (58) Fields investigated (Int. Cl. ⁶ , DB name) A63B 59 / 06

Claims (8)

(57) [Claims] 1. A baseball bat having a hitting portion for contacting a hitting ball, wherein said hitting portion comprises an elongated hollow metal tube, wherein said metal tube has an inner wall surface,
A hollow sleeve of reinforcing fibers oriented in a bi-directional pattern within a resin matrix, wherein the sleeve has thousands of pounds per square inch between an inner wall surface of the metal tube and an outer wall surface of the sleeve. A baseball bat, which is compressed and restrained in the metal tube by a compressive force of the order: 2. The sleeve is woven,
The baseball bat according to claim 1, wherein the reinforcing fibers include carbon. 3. The baseball bat according to claim 2, wherein said reinforcing fibers are oriented at 0 ° and 90 ° with respect to the axis of said metallic tube. 4. The baseball bat according to claim 3, wherein said metal tube has a thin wall portion including a recess, and said sleeve is fitted in said recess. 5. The thin wall portion has a thickness of 1.27 mm.
5. The baseball bat according to claim 4, wherein said baseball bat has a length of (0.05 inch) to 2.032 mm (0.089 inch). 6. The baseball bat according to claim 4, wherein said metal tube is made of aluminum. 7. The baseball bat according to claim 1, wherein the reinforcing fibers are graphite. 8. The baseball according to claim 4, wherein the baseball bat further includes a step of applying an adhesive layer between an inner wall surface of the metal tube and an outer wall surface of the hollow sleeve. bat.